Suspension system

ABSTRACT

Disclosed herein is a suspension system incorporating three inline wheels for supporting one side of a vehicle. Each end wheel is connected to and cooperates with a hydraulic cylinder. The middle wheel is connected to and cooperates with a pair of hydraulic cylinders. A tubular line connects the hydraulic cylinder of one end wheel with one of the hydraulic cylinders of the middle wheel, and a tubular line connects the hydraulic cylinder of the other end wheel with the other hydraulic cylinder of the middle wheel.

United States Patent [72] Inventors John B. Shaw 1812 E. Marlette,Phoenix, Ariz. 85016; William H. Schwartz, 260 Summit Drive, CorteMadera, Calif. 94925 Appl. No. 789,905

... Filed Jan. 8, 1969 [45] Patented Jan. 19, 1971 [54] SUSPENSIONSYSTEM 8 Claims, 6 Drawing Figs.

[52] US. Cl 280/1045, 280/81 [51] Int. Cl 860g 5/00 [50] Field ofSearch280/81 104.5. 124F [56] References Cited UNITED STATES PATENTS 2,395.6402/1946 Pearson 280/81 Primary Examiner-Philip Goodman Att0rneyMellin,Moore & Weissenberger ABSTRACT: Disclosed herein is a suspension systemincorporating three in-line wheels for supporting one side of a vehicle.Each end wheel is connected to and cooperates with a hydraulic cylinder.The middle wheel is connected to and cooperates with a pair of hydrauliccylinders. A tubular line connects the hydraulic cylinder of one endwheel with one of the hydraulic cylinders of the middle wheel, and atubular line connects the hydraulic cylinder of the other end wheel withthe other hydraulic cylinder of the middle wheel.

PATENTEB JAN 1 9 l9?! SHEET 1 BF 3 l NV FN'TTWS JOHN B. SHAW BY WILLIAMH. SCHWARTZ ATTORNEYS PATENTEU JAN 1 9 I97! SHEET 3 0F 3 IIB H. 8 1| 5 l5 (I o o 0 w o o l o o 01 \l a D m m INVFNTORS JOHN B. H BY WILLIAM H.SCElWfikTZ wzfl MPW ATTORNEYS SUSPENSION SYSTEM BACKGROUND OF THEINVENTION This invention relates to a vehicle suspension system, andmore particularly to a suspension system which incorporates aload-equalizing apparatus.

In the prior art, various devices are known which incorporate aload-equalizing or stabilizing mechanism through which two or morewheels of a vehicle interact. See, for example, U.S. Pat. Nos. 3,l95,9l7(Baldock), 1,747,902 (Marcum), 3,239,236 (Flowers), 2,381,425 (Deal etal.), 3,134,606 (Oyler), and 2,691,420 (Fox et al.). In such devices,the wheels along one side of the vehicle interact to stabilize that sideof the vehicle and/or equalize the load over those wheels. 1

It will be noted that the patents to Baldock, Marcum, Flowers, Deal etal. and Fox et al. each teach a two-wheeled system, with interactiontherebetween, in some cases by hydraulic means (Baldock, Flowers, Dealet al.), and in some cases by pneumatic means (Marcum, Fox et al.).Nowhere is there a teaching of how to tie in the wheels of a three- (ormore-) wheeled system by hydraulic or pneumatic means so that stabilityand/or load equalizing between these wheels is achieved. It would beobvious, of course, to add wheels to any of the vehicles of thesepatents. But there is no teaching of how proper load equalizing could beachieved when these wheels are so added.

The patent to Oyler discloses a system which causes stabilizing betweenthree wheels on one side of a vehicle. But that system is purelymechanical, involving long leaf springs and chains interconnecting them.Such a system can only be applied, of course, when the structure ofthe'vehicle allows room for it. As is well known, often theconfiguration of the structure will not allow it, and it would thereforebe advantageous to provide a hydraulic system (wherein hydraulic linescan be bent and configured to fit the vehicle structure) in its place;

It is therefore the object of this invention to provide a hydraulicsuspension system for a vehicle which provides load equalization overthree wheels along one side of the vehicle.

It is a further object of this invention to provide a system which,while fulfilling the above object, provides proper springing action andshock absorption for the vehicle.

It is a still further object of the invention to provide a system which,while fulfilling the above objects, is as simple and maintenance-free aspossible.

SUMMARY OF THE INVENTION Broadly stated, the inventive suspension systemis associated with the frame of a vehicle for supporting one side of theframe above the ground and comprises first, second and third wheelsassociated with the frame, the axles of the wheels being movablerelative to the frame along lines substantially perpendicular to theground. A first hydraulic cylinder has its body fixed relative to theframe above the axle of the first wheel and its piston fixed relative tothe axle of the first wheel to move therewith. A second hydrauliccylinder has its body fixed relative to the frame above the axle of thethird wheel and its piston fixed relative to the axle of the third wheelto move therewith. A linkage bar has its center portion pivotally fixedrelative to and above the axle of the second wheel. A third hydrauliccylinder has its body fixed relative to the frame and above one end ofthe linkage bar, and its piston rod pivotally fixed relative to that oneend of the linkage bar. A fourth hydraulic cylinder has its body fixedrelative to the frame and above the other end of the linkage bar, andits piston rod pivotally fixed relative to the other end of the linkagebar. A first tube interconnects the first and third hydraulic cylindersfor the interchange of pressure therebetween, and a second tubeinterconnects the second and fourth hydraulic cylinders for theinterchange of pressure therebetween.

BRIEF DESCRIPTION OF THE DRAWINGS These and other objects of theinvention will become apparent from a study of the following descriptionand drawings, in which:

FIG. 1 is a perspective view, partly in phantom, of a vehicle whichincorporates the inventive suspension system;

FIG. 2 is a side elevation of a portion of the vehicle of FIG. I,showing the suspension system;

FIG. 3 is a view taken along the line 3-3 of FIG. 2;

FIG. 4 is a sectional view with portions removed, of the suspensionsystem;

FIG. 5 is a side elevation partly broken away, of the portion of thesuspension adjacent the center wheel of one side of the vehicle;

FIG. 6 is a view taken along the line 6-6 of FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENT Generally shown in FIG. 1 is avehicle 10. The vehicle 10 is shown as one which is adapted to lift andcarry shipping containers, but it will be understood that the suspensionsystem disclosed is adaptable to any vehicle. The vehicle 10 comprises aframe 12 which includes longitudinal subframe portions 14 and 16. Thesubframe portion 14 has equally spaced and aligned wheels 18, 20, 22associated with it and the subframe portion 16 has equally spaced andaligned wheels 24, 26, 28 associated with it. The manner of associationof the wheels 18, 20, 22 with the subframe portion 16 is best shown inFIGS. 2-6.

The tubular body 30 of a hydraulic cylinder 32 is fixed to thelongitudinal subframe portion 14 at one end thereof. Disposed within thebody 30 is a piston 34 which is fixed to a suspension arm 36 which inturn is fixed relative to axle 38 of wheel 18. By sliding the piston 34up and down within the tubular body 30, the axle 38 of wheel 18, it willbe seen, is movable up and down along a line substantially perpendicularto the ground 40 on which the vehicle 10 rides.

At the other end of the longitudinal subframe portion 14 is fixed thetubular body 41 of a hydraulic'cylinder 42. Disposed within the body 41is a piston 43 which is fixed to a suspension arm 44 which in turn isfixed relative to axle 46 of wheel 22. The axle 46 of wheel 22 ismovable up and down along aline substantially perpendicular to theground 40 by sliding piston 43 within tubular body 41, this motion beingsimilar to the motion of axle 38 of wheel 18 previously described.

Mounted to the subframe portion 14 between the hydraulic cylinders 32,42 and above the wheel 20 is a tubular guide 48. The guide 48 hasslidably disposed therewithin a tubular member 50, the bottom portion ofwhich is fixed to a suspension arm 51 in turn fixed relative to the axle52 of the wheel 20. By sliding the tubular member 50 up and down withinthe guide 48, the axle 52 of wheel 20 is movable along a linesubstantially perpendicular to the ground 40. A pivotal connecting link54 interconnecting the tubular member 50 and subframe portion 14 acts tokeep these members in their proper relative positions.

As shown in FIG. 2, the suspension arm 36 acts as a connecting rodbetween piston 34 and axle 38, and the suspension arm 44 acts as aconnecting rod between piston 43 and axle 46.

A pin 56 is fixed within the inner bore of tubular member 50. A linkagebar 58 has its center, portion pivotally fixed about the pin 56 at apoint above the axle 52 of the wheel 20, the tubular member 50 havingopenings to allow such pivoting. The tubular bodies 60, 62 of hydrauliccylinders 64, 66 are fixed to the longitudinal subframe portion 14 oneither side of the tubular guide 48. and above the ends 58A, 58B oflinkage bar 58. The piston rod 68 of hydraulic cylinder 64 is pivotallyfixed at one end to the piston 70 thereof, and is pivotally fixed at itsother end to the end 58A of linkage bar 58. The piston rod 72 ofhydraulic cylinder 66 is pivotally fixed at one end to the piston 74thereof, and is pivotally fixed at its other end to the end 58B oflinkage bar 58. A spring member 76 is disposed between the end 58A ofthe linkage bar 58 and the bottom of body 60 of hydraulic cylinder 64.Similarly, a spring member 78 is disposed between the end 588 of thelinkage bar 58 and the bottom of the body 66 of hydraulic cylinder 62.

As best shown in FIGS. 2 and 4, a hydraulic line or tube 80interconnects the hydraulic cylinders 32 and 64. Similarly, a hydraulicline or tube 82 interconnects the-hydraulic cylinders 66 and 42.

Disposed over the hydraulic cylinder 32 and communicating with the tube80 is a reservoir 86. Disposed over the hydraulic cylinder 42 andcommunicating with the tube 82 is a reservoir 88. Restrictive orifices90, 92 are included where these reservoirs 86, 88 communicate with thetubes 80, 82 respectively, n

In operation, the hydraulic cylinders 32, 64, 66, 42. tubes 80. 82, andreservoir 86, 88 are filled with hydraulic fluid 94 while the pistons ofthese cylinders are in their highest positions relative to the-bodiesthereof. Nitrogen 96 is then forced into the reservoirs 86, 88 until thepistons of the cylinders 32, 64, 66,42 are moved'8 inches downward, thepressure raising the subframe portion 14 of vehicle 10 so that it issuspended on wheels 18, 20, 22.

it will be understood that a similar suspension system is associatedwith the subframe portion 12 so that the whole vehicle 10 is suspended.

If, as the vehicle 10 is moving, a sudden upward load is placed on wheel18, as by hitting a bump, an increased pressure is set up in hydrauliccylinder 32, which pressure is communicated to hydraulic cylinder 64through tube 80 by the fluid 94 therein. The increased pressure inhydraulic cylinder 64 is communicated to hydraulic cylinder 66 bylinkage bar 58, acting as a lever about pin 56. The increased pressurein hydraulic cylinder 66 is communicated to hydraulic cylinder 42through tube 82. lt is to be noted that the areas of pistons 34 and 43are equal, and that each has twice the area of the pistons 70 and 74.This means that if the load on piston 34 is increased by I pounds, theload on piston 70 is increased by 50 pounds. The increased force onpiston 70 results in an increased force of 50 pounds on piston 74. Thisincreased force of 50 pounds on piston 74, because of this arearelationship. results in an increased force of 100 pounds on piston 43.it will thus be seen that the increase in force on each wheel is 100pounds (100 pounds on piston 34, connected to wheel 18; 50 pounds onpiston 70, 50 pounds on piston 74, both connected to wheel 20; and 100pounds on piston 43, connected to wheel 22). Thus, if an increased loadis placed on one of the wheels of the vehicle, the loads on the otherwheels on that side of the vehicle are increased substantially the sameamount.

it should be noted that the ends 58A, 58B of the linkage bar are angleddownward from the pin 56. As a force downward is placed on, for example,end 58A of linkage bar 58, and the linkage bar 58 pivots about pin 56,the lever arm defined between end 58A and pin 56 becomes shorter thanthe lever arm defined between end 588 and pin 56. This results in aforce less than that on piston 70 being transferred to piston 74. Thischanging lever arm, in conjunction with the spring members 76, 78,insures that the vehicle returns to a substantially level position. Whensuch load on the wheel 18 is increased, as by hitting a bump, nitrogenin the reservoirs 86, 8% acts as a spring member to absorb the shock ofthe blow. The restrictive orifices 90, 92, act as shock dampers when a bisizit by wheel E8.

it will be seen that herein is provided a hydraulic suspension systemfor a vehicle which is capable of providing load equalization over threewheels along one side of the vehicle. The system, as described, includesmeans for effectively absorbing shock and damping movement within it.The system is obviously quite simple and maintenance-free, and, itwill'be seen, can be applied quite easily to a variety of vehicles. Thesystem has been found to be extremely advantageous because of the pistonarea relationship described. Because of such area relationship, it isensured that proper load equalization over the wheels of the vehicletakes place.

We claim:

1. A suspension system associated with the frame ofa vehicle forsupporting one side of the frame above the ground comprising: 5 g,

a. first, second and third wheels disposed below the frame and rotatableabout their respective axles;

b. a first hydraulic cylinder disposed between and interconnecting theframe an and the axle of the first wheel;

. a second hydraulic cylinder disposed between and interconnecting theframe and the axle of the third wheel;

d. a linkage bar the center portion of which is pivotally fixed relativeto the axle of the second wheel:

e. a third hydraulic cylinder disposed between and interconnecting theframe and one end ofthe linkage bar:

I a fourth hydraulic cylinder disposed between and interconnecting theframe and the other end of the linkage bar;

g. a first tube interconnecting the first and third cylinders for theinterchange of pressure therebetween; and

h. a second tube interconnecting the second and fourth cylinders for theinterchange ofpressure thcrebetween.

2. A suspension system associated with the frame ofa vehicle forsupporting one side of the frame above the ground comprising: i

a. first, second and third wheels associated with the frame, the axlesof the wheels being movable relative to the frame along linessubstantially perpendicular to the ground;

b. a first hydraulic cylinder the body of which is fixed relative to theframe above the axle of the first wheel and the piston of which is fixedrelative to the axle of the first wheel to move therewith;

c. a second hydraulic cylinder the body of which is fixed relative tothe frame above the axle of the third wheel and the piston of which isfixed relative to the axle of the third wheel to move therewith;

d. a linkage bar having its center portion pivotally fixed relative toand above the axle of the second wheel;

e. a third hydraulic cylinder the body of which is fixed relative to theframe and above one end of the linkage bar and the piston rod of whichis pivotally fixed relative to that one end of the linkage bar;

a fourth hydraulic cylinder the body of which is fixed relative to theframe and above the other end of the linkage bar and the piston rod ofwhich is pivotally fixed relative to that other end of the linkage bar;

a first tube interconnecting the first and third hydraulic cylinder forthe interchange of pressure therebetween;

and

h. a second tube interconnecting the second and fourth hydrauliccylinders for the interchange of pressure therebetween.

3. A suspension system according to claim 2 wherein the area of thepiston of the first hydraulic cylinder is approximately twice the areaof the piston of the third hydraulic cylinder, and the area of thepiston of the second hydraulic cylinder is approximately twice the areaof the piston of the fourth hydraulic cylinder.

4. A suspension system according to claim 3 wherein is further includeda first reservoir disposed above and communicating with the first tube,-and gaseous matter within the first reservoir, and a second reservoirdisposed above and communicating with the second tube, and gaseousmatter within the second reservoir.

5. A suspension system according to claim 4 and further includingrestrictive orifices in the first and second tubes where the first andsecond reservoirs communicate with the first and second tuberespectively.

6. A suspension system associated with the frame of a vehicle forsupporting a longitudinal side portion of the frame above the groundcomprising:

a. first, second and third wheels which are associated with the frame.the axles of the wheels being movable relative to the longitudinal sideportion along linessubstantially perpendicular to the ground. the first,second and third wheels being substantially aligned with the secondwheel intermediate and equally spaced from the first and third wheels;

a first hydraulic cylinder the body of which is fixed relative to thelongitudinal side portion above the axle of the first wheel and thepiston of which is fixed relative to the axle of the first wheel to movetherewith;

a second hydraulic cylinder the body of which is fixed relative to thelongitudinal side portion above the axle of IO the third wheel and thepiston of which is fixed relative to the axle of the third wheel to movetherewith;

a linkage bar having its center portion pivotally fixed relative to andabove the axle of the second wheel;

a third hydraulic cylinder the body of which is fixed relative to thelongitudinal side member and above one end of the linkage bar and thepiston rod of which is pivotally fixed relative to that one end of thelinkage bar;

f. a fourth hydraulic cylinder the body ofwhich is fixed relative to thelongitudinal side member and above the other end of the linkage bar andthe piston rod of which is pivotally fixed relative to that other end ofthe linkage bar;

g. a first tube interconnecting the first and third hydraulic cylindersfor the interchange of pressure therebetween; and

h. a second tube interconnecting the second and fourth hydrauliccylinders for the interchange of pressure therebetween.

7. A suspension system according to claim 6 wherein the areas of thepiston of the first and second hydraulic cylinders are approximatelyequal. the area of the piston of the first hydraulic cylinder isapproximately twice the area of the piston of the third hydrauliccylinder. and the area of the piston of the second hydraulic cylinder isapproximately twice the area of the piston of the founh hydrauliccylinder.

8. A suspension system according to claim 7 and further including afirst reservoir disposed above and communicating with the first tube,and gaseous matter within the first reservoir, and a second reservoirdisposed above and communicating with the second tube. and gaseousmatter within the second reservoir, and further including restrictiveorifices where the first and second reservoirs communicate with thefirst and second tubes respectively.

1. A suspension system associated with the frame of a vehicle forsupporting one side of the frame above the ground comprising: a. first,second and third wheels disposed below the frame and rotatable abouttheir respective axles; b. a first hydraulic cylinder disposed betweenand interconnecting the frame an and the axle of the first wheel; c. asecond hydraulic cylinder disposed between and interconnecting the frameand the axle of the third wheel; d. a linkage bar the center portion ofwhich is pivotally fixed relative to the axle of the second wheel; e. athird hydraulic cylinder disposed between and interconnecting the frameand one end of the linkage bar; f. a fourth hydraulic cylinder disposedbetween and interconnecting the frame and the other end of the linkagebar; g. a first tube interconnecting the first and third cylinders forthe interchange of pressure therebetween; and h. a second tubeinterconnecting the second and fourth cylinders for the interchange ofpressure therebetween.
 2. A suspension system associated with the frameof a vehicle for supporting one side of the frame above the groundcomprising: a. first, second and third wheels associated with the frame,the axles of the wheels being movable relative to the frame along linessubstantially perpendicular to the ground; b. a first hydraulic cylinderthe body of which is fixed relative to the frame above the axle of thefirst wheel and the piston of which is fixed relative to the axle of thefirst wheel to move therewith; c. a second hydraulic cylinder the bodyof which is fixed relative to the frame above the axle of the thirdwheel and the piston of which is fixed relative to the axle of the thirdwheel to move therewith; d. a linkage bar having its center portionpivotally fixed relative to and above the axle of the second wheel; e. athird hydraulic cylinder the body of which is fixed relative to theframe and above one end of the linkage bar and the piston rod of whichis pivotally fixed relative to that one end of the linkage bar; f. afourth hydraulic cylinder the body of which is fixed relative to theframe and above the other end of the linkage bar and the piston rod ofwhich is pivotally fixed relative to that other end of the linkage bar;g. a first tube interconnecting the first and third hydraulic cylinderfor the interchange of pressure therebetween; and h. a second tubeinterconnecting the second and fourth hydraulic cylinders for theinterchange of pressure therebetween.
 3. A suspension system accordingto claim 2 wherein the area of the piston of the first hydrauliccylinder is approximately twice the area of the piston of the thirdhydraulic cylinder, and the area of the piston of the second hydrauliccylinder is approximately twice the area of the piston of the fourthhydraulic cylinder.
 4. A suspension system according to claim 3 whereinis further included a first reservoir disposed above and communicatingwith the first tube, and gaseous matter within the first reservoir, anda second reservoir disposed above and communicating with the secondtube, and gaseous matter within the second reservoir.
 5. A suspensionsystem according to claim 4 and further including restrictive orificesin the first and second tubes where the first and second reservoirscommunicate with the first and second tube respectively.
 6. A suspensionsystem associated with the frame of a vehicle for supporting alongitudinal side portion of the frame above the ground comprising: a.first, second and third wheels which are associated with the frame, theaxles of the wheels being movable relative to the longitudinal sideportion along lines substantially perpendicular to the ground, thefirst, second and third wheels being substantially aligned with thesecond wheel intermediate and equally spaced from the first and thirdwheels; b. a first hydraulic cylinder the body of which is fixedrelative to the longitudinal side portion above the axle of the firstwheel and the piston of which is fixed relative to the axle of the firstwheel to move therewith; c. a second hydraulic cylinder the body ofwhich is fixed relative to the longitudinal side portion above the axleof the third wheel and the piston of which is fixed relative to the axleof the third wheel to move therewith; d. a linkage bar having its centerportion pivotally fixed relative to and above the axle of the secondwheel; e. a third hydraulic cylinder the body of which is fixed relativeto the longitudinal side member and above one end of the linkage bar andthe piston rod of which is pivotally fixed relative to that one end ofthe linkage bar; f. a fourth hydraulic cylinder the body of which isfixed relative to the longitudinal side member and above the other endof the linkage bar and the piston rod of which is pivotally fixedrelative to that other end of the linkage bar; g. a first tubeinterconnecting the first and third hydraulic cylinders for theinterchange of pressure therebetween; and h. a second tubeinterconnecting the second and fourth hydraulic cylinders for theinterchange of pressure therebetween.
 7. A suspension system accordingto claim 6 wherein the areas of the piston of the first and secondhydraulic cylinders are approximately equal, the area of the piston ofthe first hydraulic cylinder is approximately twice the area of thepiston of the third hydraulic cylinder, and the area of the piston ofthe second hydraulic cylinder is approximately twice the area of thepiston of the fourth hydraulic cylinder.
 8. A suspension systemaccording to claim 7 and further including a first reservoir disposedabove and communicating with the first tube, and gaseous matter withinthe first reservoir, and a second reservoir disposed above andcommunicating with the second tube, and gaseous matter within the secondreservoir, and further including restrictive orifices where the firstand second reservoirs communicate with the first and second tubesrespectively.